The use of nasal dilator strips is popular among athletes participating in a variety of high intensity sport activities. Their use is observed in anaerobic-type sports involving intermittent, short maximal work outputs (e.g. football, hockey, volleyball), and in aerobic-type sports, which involve continuous high intensity exercise (e.g. distance running, soccer). Currently, there is little scientific evidence that demonstrates improved athletic performance in healthy individuals during anaerobic or aerobic exercise activities. However, few studies have been designed to investigate the potential effects of training status, gender, and ethnicity. The physiologic mechanisms that might mediate improved athletic performance with the use of nasal dilator strips in healthy individuals have not been determined. A general hypothesis is that nasal strips dilate the nasal valve area of the nose, which reduces nasal airway resistance resulting in improved ventilation, pulmonary gas exchange, and arterial oxygenation. However, there is scarce information on the effects of using nasal dilator strips during exercise on physiological measures of airway function and ventilation, or pulmonary gas exchange and arterial oxygenation. The purpose of this study is to: a) Determine the potential ergonomic effects of nasal dilator strips during high intensity aerobic exercise; and b) investigate physiologic mechanisms that might mediate improved athletic performance. Specifically, the strategy of the study is to utilize a repeated measures design that examines the interactive effects of four factors (intervention, training status, gender, and ethnicity) on physiological measures of exercise performance, airway function, and pulmonary gas exchange, during high intensity aerobic exercise. A pilot study has been conducted which helped to identify study design considerations, protocol concerns, and supports our ability to successfully conduct such a study. A focus area of "Healthy People 2010" is Physical Activity and Fitness. Clarifying the exercise performance effects of nasal strips may serve the public in several ways. If nasal dilator strips enhance performance, then promoting the device might encourage more persons to attempt to engage, regularly, in moderate and vigorous physical activity. If nasal dilator strips do not improve exercise performance then this study could serve as a caution to the public to not spend their money on the device for that purpose. Furthermore, in the area of exercise science studies, there is a gross absence of participation by African Americans and women. Thus, this study can contribute new knowledge in biomedical sciences concerning the dynamics of pulmonary respiration and exercise capacity, in African Americans and women, and potentially contribute to the general goal of "Healthy People 2010", of reducing health disparities among Americans.